The following disclosure relates to a novel polymeric composite including a nanoparticle filler, and a process for making the composite. More particularly, the disclosure provides a novel method for the production of a nanocomposite including a polymer and halloysite nanoparticle filler, the filler having general shape of a cylinder or rolled scroll-like element, in which the diameter of the cylinder is less than about 500 nm. The advantages of the nanoparticle filler are provided (e.g., reinforcement, flame retardant, improved or equivalent mechanical performance) as a result of the ability to disperse the nanoparticle within and/or on the surface of a polymeric structure.
The addition of various nano-clay materials to polymer systems can lead to improved mechanical properties (such as toughness/ductility or strength) and/or thermodynamic stability. Details of such advantages as well as alternative materials and their characteristics are found, for example, in several prior patent applications relating to halloysite nanocomposites and applications thereof, including:    U.S. Provisional Application 60/713,362 for a “Polymeric Composite Comprising Halloysite,” filed Sep. 2, 2005 by S. Cooper;    U.S. application Ser. No. 11/469,128 for “Polymeric Composite Including Nanoparticle Filler” filed Aug. 31, 2006 by Sarah H. Cooper et al.; and    U.S. application Ser. No. 11/531,459 for “Radiation Absorptive Composite and Methods for Production” filed Sep. 13, 2006 by A. Wagner et al.;the disclosures of all of the above-identified applications being hereby incorporated by reference in their entirety.
Composite materials have become well known as man-made materials are increasingly substituted for raw materials in construction, fabrication and the like (e.g., automobiles, building materials, food packaging and textiles). A polymer composite includes at least one polymer matrix or material in combination with at least one particulate filler material. The polymer matrix material may be any of a number of polymers including thermoplastics such as Polypropylene, Polyaramide, Polyarylamide, Polycarbonate, Polystyrene, Styrene Acrylonitrile, Acrylonitrile Butadiene Styrene, Acetal, Polysulfone, Polybutylene Terephthalate, Polyethylene Terephthalate, Polyethylene, Thermoplastic Polyurethane Elastomer, Polyphenylene Sulfide, Polyether Sulfone, Polyphenylene Oxide, Acrylic, Polyetherimide, Polyetheretherketone, Polyetherketone, Polymethylpentene, Perfluoroalkoxy, Ethylene Tetrafluroethylene, Polyvinylidene Fluoride, Fluorinated Ethylrene Propylene, Liquid Crystal Polymers, Polyphthalamide, Thermoplastic polyimide, and other thermoplastic polymers plus blends and co-polymers and may also include polyamide (Nylon), poly-urethane, polyolefins, vinyl polymers, and the like, thermosets, and elastomers. As the understanding of the structure-property relationships of composites becomes better understood, the use of nanoparticles is of increasing interest in the formation of composites—referred to as nanocomposites. Some of the most common nanoparticle fillers are two-dimensional nanoclays, one-dimensional carbon nanotubes, and zero-dimensional metal oxide nanoparticles such as Zinc Oxide (ZnO), Titanium Dioxide (Ti02), and Zirconia (ZrOn). Composites offer the potential of materials having properties that are not often available in naturally occurring raw materials (e.g., U.S. Pat. No. 6,518,324 to Kresta et al. for a Polymer Foam Containing Nanoclay, hereby incorporated by reference in its entirety).
There are several known ways in which to form polymer nanocomposites utilizing nanoclay materials. Traditionally the processes include melt compounding (via melt extrusion of pre-treated fillers) as contrasted with the disclosed process of solution blending and in-situ treatment of the filler utilizing a master batch. The following disclosure is directed, in one embodiment, to the use of a master batch that includes a high-concentration of halloysite nanoparticles (e.g., 30% by weight of halloysite with nanotubes) produced for subsequent processing.
The advantages of a master batch or nanocomposite material produced in accordance with the description below are numerous. One advantage is that the composite exhibits better dispersion within the final material/product, resulting in improved mechanical properties because of the more consistent dispersion. Defects in the composite, due to poor dispersion, will lead to weak points in the final composite, thus compromising the mechanical properties. Another advantage is that this process makes it easier to prepare highly concentrated compounds (e.g., about 30 wt % or higher) that are desired for master batch, without the rheological limitations of melt compounding. In melt compounding processes, only a limited amount of filler can be used, due to the increase in viscosity that occurs at high loading levels, often making it impractical to extrude highly loaded materials. This process can be utilized for a wider range of polymers, since dispersion and melt viscosity issues are avoided. When using a master batch, the material may also be provided in commercial quantities to facilitate the ability of a manufacturer to utilize the material as it avoids inherent problems with handling clays (e.g., dusting). The same advantages set forth apply for use of the material as well.
Disclosed in embodiments herein is a method of production of a polymer nanocomposite master batch, comprising: dissolving a polymer (e.g., a soluble polymer) in a solvent to produce a polymer solution; adding a dispersing aide to the polymer solution; further combining a filler material (e.g., a nanomaterial including a processed clay material such as halloysite) to the polymer solution to produce a dissolved polymer intimately mixed with the nanocomposite material (mixture); and causing the precipitation of the mixture to produce a nanocomposite master batch.
Further disclosed in embodiments herein is a method of making a polymer nanocomposite, comprising: dissolving a polymer in a solvent to produce a polymer solution; adding a dispersing aide to the polymer solution; further combining a filler material to the polymer solution to produce a dissolved polymer intimately mixed with the nanocomposite material (mixture); and causing the precipitation of the mixture to produce a nanocomposite material.
Also disclosed in embodiments herein is a polymer nanocomposite material, comprising: from about 5 wt % to about 60 wt % of a nanocomposite filler; and a polymer.
The various embodiments described herein are not intended to limit the disclosure. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope defined by the appended claims.